A Technical Manual for Landowners, Loggers, and ... - Forestry

R O A D S, S K I D T R A I L S , L A N D I NG S & S T R E A M C R O S S I NG S
R O A D S, S K I D T R A I LS , L A N D I NG S
& S T R E A M C R O S S I NG S
■ For safety reasons, avoid out-sloping roads on steep slopes
S u rface Dra i n a ge
The most effective method to control erosion on forest roads is to keep water
f rom accumulating on the road surface. Erosion from road surfaces can be cont
rolled when water is diverted and dispersed into vegetation and ground litter.
The use of water diversion devices or drainage stru c t u res such as rolling dips,
diversion Figure 4.3 ditches, cross culverts and water bars can be used to prevent ero s i o n .
Poor road dra i n a ge - wa ter should not be allowed to run down a road for any dista n c e .
B road Based or Rolling Dips
A broad based or rolling dip is much like a hump constructed in the road bed
to divert water off the road. A well constructed broad based dip is deep enough
to provide adequate drainage and wide enough to allow trucks and equipment
to pass safely. The rolling dip is constructed at an angle toward the direction of
the road for ease of travel. The bottom of the dip is sloped to the outside to carry
water away from the road. Broad based or rolling dips are best suited to ro a d
grades of 10% or less and should be spread out over a minimum of 150 feet.
Figure 4.4 Rolling Dip
Adapted from The Bureau of Forestry, Wisconsin Department of Natural Resources
Figure 4.5 Rolling Dip Cross-Section
Original Grade
Construction
Photo: Darren McAvoy
Final Grade
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